Musings about big IT in a small world

non-IT how to – Bosch VP44/PSG-16 “camshaft” hall sensor fix

My mother-in-law happens to own Opel (or Vauxall in some countries where they drive on wrong side) Zafira A with Y22DTR diesel engine. Fuel pump in that engine is Bosch VP44 with PSG-16 management unit. For one reason or another Bosch has decided not to sell any spares for this specific version of pump. At the same time, there is single part that is prone to fail in these pumps and that part is hall sensor that measures pump shaft rotation (if you try to read ECU fault codes it is called “camshaft” sensor, but actually it is housed in pump itself). And of course this sensor failed.
So I searched around just to find that nobody would replace sensor alone, only whole pump assembly, which means ~2000 Euros around here. Neither did I accept the fact that I have to pay 2000 Euros for a repair of part that costs less that 10, nor did I have spare pile of Euros to throw in the car that by now has a value of around 4000 Eur.
First I tried to use some off the shelf hall sensor bought from Farnell, it was a bit too high (or thick depending on how you look at it) and was getting in a way of sensor wheel teeth. Next I found that the same sensor from different model of the same pump – VP44/PSG-5, looks the same and can actually be bought as a spare. The only obvious difference between PSG-5 and PSG-16 sensors is flat cable assembly that is integral part of sensor.
Next step was to source used, but known good sensor from PSG-5 and try to figure how to implant that into PSG-16. Solution was apparent because part of cable going into the sensor is of the same width on both sensors and seemed to have the same trace layout. So both cable assemblies were cut in a place where width matches, leaving a little bit longer cable ends to make them overlap and at the same time provide for necessary total length. Then plastic, that makes up cable body, was scraped off of one side of cable going to management unit revealing clean copper traces. Thin layer of solder was applied to those traces (I used desoldering wick to remove excess solder) and the same was repeated with the opposite side of cable coming from sensor. At this point I should have used some fuel resistant heatshrink tubing (like Tyco/Raychem DR-25) to make it sturdier, but I did not have it at hand. So I just went ahead and pressed both cable ends together and heated them with soldering iron. That provided for good enough electrical connection. Then some superglue was applied to the joint to make it stronger physically and sensor was soldered back to pump management unit.
Next day revealed that both sensors are indeed the same and after removing air from fuel lines engine happily started again.
1950 Euros saved and Bosch vs hackers – 0:1.

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This is a very good idea! It is a good news.
I have some few questions about your experience.
How did you get the default code? Was it with a generic OBD system or with an opel system? What kind of code did you obtained?
I have some problème with a SSAB 93.
SAAB told us that the PSG16 pump was out of order and the repair would cost about 5130 euros!

I don’t remember exact codes, but those were related to camshaft sensor (could be 0340). ESI[tronic] by Bosch was used for diagnostics, but any tool capable of reading codes from PSG16 should do the trick. If you have tool that can show you realtime values of different sensors, check that camshaft sensor has ~2x revs than crankshaft, if not or if readings are jumpy, that’s your culprit! Disassembly of pump is better left to someone familiar with those things because it is very easy to break the flat cable going to sensor but that is something you do not want.
On PSG16 this darned hall sensor is almost only thing that breaks, so I have heard.

thanks for the answer.
I have made a DIY obd tester, based on Elm327 device, and a PC as terminal. But the codes revealed by the system are not the same. Only two codes: P0670 & P1404. But, I think that saab erased the latest trouble code when they diagnosed the vehicule…
This saab is not the mine, and i will examine it as soon as possible. Perhaps, there is no problem with this pump but with a litle durit or a sensor, or actuator… I will verify the fuel trip, and the sensors value (I get the SAAB WIS Software wich is a good starting point).
In summary, you shared an important information for all other guys, and I like it!
Thanks to you, I will come to you for the end of the story.

P0670 is glow plug controller and P1404 is EGR. If EGR is faulty car should go in limp mode, but still run. None of those errors is directly related to pump itself. If pumb hall sensor is faulty, it will come up as soon as you try to crank. Can you get your hands on ESI[tronic] or any other more professional test equipment, DIY is fun, but pro stuff is easier to work with and gives faster/better result 🙂

yes, sensor is under ecu, exactly the same as in psg5. and yes, ecu and sensor were removed with pump still on the vehicle, but you have to be very careful when removing ecu/sensor as it is easy to break flat cable going to sensor. so if that really is “crankshaft sensor” that gives you error and you can get your hands on working sensor from psg5 and have some soldering skills, go ahead, save yourself a pile of kronor.

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